Machine for producing compressed gases operating more particularly like free piston machines



Sept. 24, 1957. E. P. BuRloN MACHINE EoR RRoDucING coMRREssED GAsEs OPERATING MORE PARTICULARLE LIKE FREE RIsToN MACHINES INI/mwa.

Filed May 9, 1955 United States Patent() MACHINE FOR PRODUCING COMPRESSED GASES OPERATING MORE PARTICULARLY LIKE FREE PISTON MACHINES This invention relates to machines operating like the machines known as free piston machines. lt applies more particularly either to motor-compressors used for delivering compressed air, or to self-generators used for delivering a mixture of compressed air and incompletely expanded combustion gas.

As is well known, one of the characteristics of free' piston machines lies in the possibility of being able to Vary the delivery per stroke, by Varying the length of the stroke of the movable elements, which enables very great flexibility to be obtained.

The main purpose of the invention is to produce a new machine in which the movable elements are always guided in a simple manner and arranged so as to be permanently equilibrated by a low inertia synchronizing system, which enables the machine to be operated quicker than with ordinary machines, by thus making it possible to manufacture machines of relatively high power and light weight, as Well vas machines of low power.

Still another advantage of the machine according to the invention is that its dimensions are reduced and that it is possible, for a given motive cylindric capacity, to obtain a cooling system that is appreciably more efficacious than that which can be obtained on an ordinary machine. Moreover, the arrangement of the members of the machine enables the section of the scavenging and exhaust ports to be increased.

According to the invention, the machine comprises two motor cylinders which extend parallel to one another, in which two sets of pistons are placed, each set of pistons being connected to at least one compressor piston, so as to form two movable elements working inopposition, these movable elements being connected to each other kby at least two connecting-rods articulated at the ends of one crank or several cranks whose rotation axis passes between the two said motor cylinders connected to each other by at least onecomrnunicating channel, for equalising the pressure set up inside these cylinders. p n

Various other characteristics of the invention will moreover be revealed in thevfollowing detailed description and claims.

Forms of embodiment of the purpose of the invention are shown, by way of non-restrictive examples, in the attached drawings. l

Figure 1 is a diagrammatic longitudinal cross-section showing a tirst form of embodiment of the machine according to the invention.

Figure 2 is a cross-section taken substantially along the line II--II of Figure l. f

Figure 3 is a similar longitudinal cross-section to Figure l, illustrating an alternative form of embodiment.

Figure 4 is a cross-section along the line IV-IV of Figure 3.

k The machine shown in the drawing comprises a casing 1 forming its framework, in which two motor cylinders 2 and 3 are made, whose longitudinal axes are parallel.

The cylinders 2 and 3 are in unrestricted communication with each other by the channels 4 and 5, according ice to the form of embodiment of Figure 1, or by one channel 4 only, according to the form of embodiment of Figure 3. l y

6 and 7 designate openings for positioning fuel injec- Vtion devices by which the fuel is injected into the cylinders 2, 3.

Scavenging ports 8 and exhaust ports 9 are spaced distantly on either side of the openings 6, 7 in the cylinders 2, 3. v

The cylinders 2 and 3 are surrounded for the whole or part of their length by jackets 10 forthe circulating of a cooling liquid, such as water.

As will be clearly seen in Figure 3, the exhaust ports 9 communicate with an exhaust gases collector ring 11. Each of the cylinders 2 and 3 contain two pistons 12, 13, and 12a, 13u respectively, intended to be driven in opposition in the manner of the pistons of machines called free piston machines, or the like.

As can be seen, the channels 4 and 5, in the case of VFigure 1 and only the channel 4 in the case of Figure 3, are intended to ensure communication in a permanent manner between said two cylinders 2, 3 so that at all times the pressure is equalized that prevails inside the latter, for securing rigorously similar action for each of these pistons 12, 13 and 12a, 13a.

The casing 1 is connected by each of its two sides to jackets 14, 15 that internally delimit the cylinders 16, 17 in which large section compressor pistons 18 and 19 are arranged.

As shown both in Figure 1 and in Figure 3, the pistons 18 and 19 are respectively rigidly attached to the pistons 412 and 12a and 13 and 13a. Furthermore, in the form of Figure l, the compressor piston 19 is connected, by its face opposite to that directed towards the motor pistons 12, 12a, to :a piston 20 that slides in a cylinder 21 formed at the end of the jacket 15, so that a certain quantity of air is trapped inthe space that it delimits, this air being intended to be compressed during the driving stroke of the pistons 12, 12a, so as to restore the power thus accumulated to bring about the return stroke of the pistons 12, 12a and 13, 13a, by ensuring the compression of the fuel mixture which is conveyed at ports 6 and 7 into the cylinders 2 and 3.

The movable elements formed, on the one hand, by the pistons 13, 13a and 18, then, on the other hand, by the pistons 12, 12a, 19 and 20, must have the same mass in the case of equal displacements, and in the case of unequal displacements, masses inversely proportional to the displacements.

According to the form of embodiment of Figures l and 2, to synchronize the movements of the movable elements, the latter :are linked together by means of two articulated systems, moving in vertical-and preferably symmetrical-planes with regard to the axis perpendicular to the axis of a synchronizing shaft 22.

As will be seen in Figure 2, the shaft 22 revolves in bearings 23, 24 integral with Vthe casing 1 through which -it passes by a bore ZS made in the partition 26 separating the two motor cylinders 2, 3. l

The connecting systems of the two sets of movable equipments comprise cranks 27, 28 keyed on the ends of the shaft 22. The cranks 27, 28 respectively have their two ends articulated to the feet of connecting-rods 29, 30 and 31, 32 whose heads are articulated, on the one hand on an axle 33 connected to the piston 19, and on the other hand, on an axle 34 connected to the piston 18.

When the two movable elements are intended to have equal displacements, the four crank arms are of equal length and when the movable elements have respectively diierent displacements, the two crank arms with the same length are those that connect by connecting-rods the same movable element` The length of the connecting-rods and the crank arms is selected so that the movable t'ree machine, i. e., when the cranks revolve at an angle exceeding `180", but less than 360, as occurs for high outputs of the` machine.

The lay-out of the machine `described above enables the motor cylinders to be properly guided, on account of their arrangement, so that the synchronizing members, i. e., the cranks 27, 28 and the connecting-rods 29 to 32 are not subjected to stresses other than those for which they are intended, and that there is no necessity to make provision for particular fittings for guiding the moving arts. i p Another advantage of the'machine described is to considerably increase the section for the passage of the gases into the scavengingand exhaust ports.

With regard to the entry of the scavenging air and the exit `of `the exhaust gases, it is possible to make them common to both cylinders 2, 3,;or, on the other hand, this entry and exit can be separated for each of l,these two cylinders.

According to an` alternative` form of `embodiment `,of Figures 3 and 4, showing a self-generator, the pistons 18 and 19 are respectively connected to the motor pistons13, 13a and 12, 12a, by means, forexample, `of hollow rods 33,\whose section depends more particularly `on the way the machine works.

In `that which` follows, it willbe .considered that the machine is ,double acting, and consequently, the rhollow connection rods 33 are relatively `of large section.

To simplify the construction of the machine, itis advantageous that the rods 33 should be `fixed in an `absolutely rigid manner to the motor pistons `13, 13a and 12, 12a `whereas theyy are connected, in an easily dismountable manner, to the compressor pistons 18, 19. The

rods 33 are guided in the bores of partitions 34 closing the bottom of the cylinders 16,117 and delimiting chambers 35 with the ends of the casing 1. Moreover, the rods 33 are advantageously open at their ends connected to the compressor pistons,` in order 4to ensure the cooling ofthe bottom of the motive pistons.

In order to obtain complete uid-tightness between the partitions 34 and the -rods 33, it` is advantageous to place duid-tight packing 34a in the grooves of the bores of the partitions 34,

36 designates guiding and 4connection rods for the pistons 18 and` 19, these rods respectively passing through the partitions 34 by `bores provided for the purpose and comprising, at their end opposite to which said pistons are fixed, articulation axles 3940 of the heads of lconnecting-rod heads 29, 30 similar to those described above, which are arranged in the same plane and so that they can -oscillate `freely in a housing 38 made in the thick partition 26 which separates the `cylinders 2, 3.

The feet of the connecting-rods 29, 30 are articulated on Vcrank-pins 39, 40 of a crank 27, whose middle part is mounted so as to be able to revolve freely on an antifriction ring `or bearing 41, surrounding an axle 42 which makes or which is made up inside the partition 26.

, In the `case `of a symmetrical machine, Vsuch as shown in the drawing, the length lof the connecting-rods 29, `30 is equal?, and selected, as in the preceding `forni of embodiment, so that these connecting-rods are placed inthe extension of `each other, when the two sets of moving parts of `the machine are placed at their external dead centre.

As stated above, themachine being intended to t operate accordingto the principle of machines called"free piston machines, the crank A27` never makes `a complete rotation, so that it is not necessary .for the connecting-rods to he placed `in two different planes, but on the contrary, it is advantageous that ztheir longitudinal axis be `placed vexactly in the same plane, so as to ensure a perfect balancing of the moving parts.

The crank 27 advantageously comprises at least one circular web 43 provided with gearing 44 `for driving the pump or pumps for fuel injection (not shown) as well as to drive the various working parts of the machine.

In the form of embodiment shown in Figures 3 and 4, according to which the machine is intended to operate as a double acting generator, the jackets 14,15 comprise the intake flap valves 45, 46, and the exhaust flap valves 47, 48 with at least one communication by a port 49 for the air delivered by the ap valve 47.

As will be seen from the drawing, the exhaust ap valve or ap valves 47 `for the up stroke are placed at a certain distance from the bottom of the cylinders, so that a charge of air is trapped in the latter to form a cushion intended to store up, as is well known, during the up stroke of the pistons, a certain amount of energy which is restored to bring about their down stroke and ensure the compression of the fuel mixture which is in that part of the cylinders 2, 3 comprised between the pistons 12, 13 and 12a, 13a.

Filters 50 for the air intake are advantageously mounted on the intake of the compressor parts of the machine.

The invention is not restricted to the examples of embodiment shown and described in detail, for various modifications can be applied to them without going outside the scope of the invention for that purpose.

I claim:

l. A machine operating on the principle of a free or semi-free piston type motor compressor, comprising two movable elements each consisting of two parallel motor pistons and at least one compression piston rigidly connected to both motor pistons, a housing formed with two parallel motor cylinders, separated by a partition, and open at their ends for the reception of the two motor pistons of each of the two elements, two casings each rigid with said housing at the respectively opposite ends thereof, located outwardly of the motor cylinders, and formed to define compression cylinders symmetrically disposed with relation to the axes of the motor cylinders, the vcompression pistons of the respective elements being reciprocable in the corresponding compression cylinder, a two-arm crank journaled for oscillation upon an axis disposed transversely through the partition, and connecting rods interconnecting the respective arms of said crank and its respective one of the two elements.

2. A machine according to claim l in which said two movable elements are of the same mass and said connecting rods of the same length.`

3. A machine according to claim 1 in `which said two movable elements are of dilerent mass and said connecting rods and cranks have a length chosen inversely proportional to the mass of the movable elements. t

4. A machine, operating in the manner of the free or semi-free piston type machines, for the production of compressed gases, comprising two movable elements one of which is provided with two motor pistons and one compressor piston rigidly connected and the other with two motor pistons and two compressor pistons disposed in line, said motor and compressor pistons being rigidly connected, motor cylinders mounted in parallel relationship for the location of said motor pistons, sockets associated with said motor cylinders and in which are located said compressor pistons one of which at least is arranged to compress a charge of air causing the return stroke, an axle transversely located between said two motor cylinders at the middle portion of the length thereof and a kinematic connection rotatably mounted on said axle and connecting said movable elements.

5. A machine, operating in the manner of the free or semi-free piston type machines, for Vthe production of compressed gases, comprising two movable elements one of which is provided with Atwo motor pistons and one compressor piston rigidly connected and the other with two motor pistons and two compressor pistons of different diameters disposed in line, said motor and compressor pistons being rigidly connected, motor cylinders integral one with the other mounted in parallel relationship for the location of said motor pistons, sockets associated with said motor cylinders and in which are located said compressor pistons, one of which is arranged to compress a charge of air causing the return stroke of the movable elements, a shaft passing between said two motor cylinders, two arm cranks associated with said shaft, connecting rods connecting said `two arm cranks and said movable elements, and means controlled by one at least of said cranks to operate the working parts of the machine.

6. A machine according to claim 5, in which the motor cylinders have two ports interconnecting them when said motor pistons are near their outer dead point.

7. An internal combustion engine compressor comprising a housing formed with two parallel, adjacent motor cylinders, and with a port interconnecting said cylinders, two free motor pistons in opposed relation within the opposite ends of each cylinder, a casing at each end 0f said housing, and rigid therewith, defining a compression cylinder the axis whereof is parallel to but located intermediate the axes of the two motor cylinders, a compression piston reciprocable within each compression cylinder, and each rigidly connected to the outer ends of the two motor pistons at the corresponding end of the respective motor cylinders, cranks oscillatably mounted in the housing upon an axis transverse to the axes of and located intermediate the two motor cylinders, and intermediate their ends, and connecting rods directly connecting the outer ends of said cranks and the compression pistons.

References Cited in the le of this patent UNITED STATES PATENTS 2,083,680 Anderson June 15, 1937 2,090,424 Pescara Aug. 17, 1937 2,115,921 Steiner May 3, 1938 2,605,605 Huber Aug. 5, 1952 2,755,988 Wachsmuth July 24, 1956 FOREIGN PATENTS 999,940 France Oct.` 10, 1951 

